One type of aerosol product that has hitherto been known is configured to hold an aerosol composition including a liquid concentrate that contains active ingredients and a propellant in an aerosol container, which is a pressure resistant container having a spraying valve. The aerosol product delivers a foamy discharge as the evaporating propellant forms bubbles in the discharged liquid.
In order to achieve favorable foam-forming ability or stability of discharged foam, a liquefied gas such as liquefied petroleum gas or dimethyl ether is used as the propellant in such a foam forming aerosol product. Since these liquefied gases are combustible, there are the problems of danger in handling them depending on the environment in which they are used, and of the possibility of explosion hazards when disposing the aerosol container. Although liquefied petroleum gas and dimethyl ether produce less airborne particulate matter or greenhouse gases as compared to other fossil fuels, they may nevertheless adversely affect the environment.
A combination of compositions, such as an organic acid composition containing an organic acid such as citric acid, for example, and a hydrogen carbonate composition containing a hydrogen carbonate such as sodium hydrogen carbonate, for example, is known to form a foam as they generate carbon dioxide gas when mixed together (see, for example, Patent Literatures 1 to 3).
However, since these compositions containing organic acid and hydrogen carbonate must be separately held in tube- or cup-shaped containers that are hermetically sealed with a lid, they need to be dispensed from the respective containers and mixed when used, which is a complicated process. Moreover, they may not be mixed in an appropriate mixing ratio because of the difficulty to adjust the amount dispensed from the respective containers. Another problem is that, the compositions in the containers are exposed to the air each time they are dispensed, which may compromise their stability over a long term storage.